Abstract

Previous theories of design decision-making have discussed how designers use
analogical reasoning to quickly scope the solution space down to one viable solution.
This initial analogy forms the template of a possible action plan that is then modified to
suit the unique properties of that particular problem. This use of analogical reasoning
allows designers to quickly engage with the problem and generate a workable solution.
Our findings indicate that this initial analogy actually persists across all stages of
decision-making, and does not play a role solely during the first stage of scoping. This
analogical persistence leads to poorer design decisions.
This thesis presents a series of studies that adopt a mixed method approach to
investigating the influence of analogies on the decision-making of Interaction
Designers. We employed qualitative methods such as the Critical Decision Method for
Eliciting Knowledge (Klein, 1989), which aided in identifying analogical persistence as
a problem that leads to poorer quality decisions. We also employed quantitative
methods such as the Design Fixation paradigm (Jansson & Smith, 1991) to investigate
how different types of analogies (self-generated & provided Priming Analogies) can
influence the expression of analogical persistence.
Finally in an attempt to mitigate the potential pitfalls of analogical persistence,
this thesis attempts to control it using principles from Design Rationale (Lee & Lai,
1991) and Reflection (Schon, 1983). Rather than seeing a decrease in analogical
persistence, our manipulation actually increased fixation. A follow-up study identified
that designers tend to poorly appraise the weaknesses in the initial analogy, which may
have led to the aforementioned unexpected result. These findings challenge the notion
that greater understanding of the design space will lead to higher quality design
decisions.